1. Field of the Invention
The present invention relates to an information processing technique and, more particularly, to a content synchronization technique.
2. Description of the Related Art
In recent years, a communication standard called UPnP (Universal Plug And Play) has attracted attention, which connects devices via a home network to share contents such as images, moving images, audios, and the like. In UPnP, a content synchronization service called CSS (Content Synchronized Service) is defined. The CSS allows to synchronize (add, delete, and change) contents or metadata of contents among a plurality of CDSs (Content Directory Services).
Japanese Patent Laid-Open No. 2010-529550 discloses a technique of causing a control point to, using the CSS, establish a synchronization relationship with a content provided by a CDS on a network. According to the method described in Japanese Patent Laid-Open No. 2010-529550, the update history of a synchronization target content is managed as a change log before the start of content synchronization. When performing content synchronization, the change log is exchanged, and the content is exchanged based on the change log. The change log is maintained even after the content synchronization, and used again in content synchronization of the next time.
According to the method described in Japanese Patent Laid-Open No. 2010-529550, however, the amount of the change log gradually increases when content synchronization is performed with various devices.